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Hognestad BW, Digranes N, Opsund VG, Espenes A, Haga HA. CO 2 Stunning in Pigs: Physiological Deviations at Onset of Excitatory Behaviour. Animals (Basel) 2023; 13:2387. [PMID: 37508164 PMCID: PMC10376161 DOI: 10.3390/ani13142387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 07/11/2023] [Accepted: 07/20/2023] [Indexed: 07/30/2023] Open
Abstract
Stunning by carbon dioxide (CO2) inhalation is controversial because it is associated with vigorous movements and behaviours which may or may not be conscious reactions. Furthermore, it is unknown whether some behaviours might indicate the transition into unconsciousness. Our study objective was to investigate the loss of consciousness during CO2 stunning by linking physiological variables (in particular pH, PaO2 and PaCO2) to the onset of observed behaviours. A total of 11 cross-bred pigs were studied. A tracheostomy tube, venous and arterial cannulae were placed under sevoflurane anaesthesia. After recovery from this, and a "wash out" period of at least 30 min, arterial blood samples were taken (and baseline values established) before 90-95% CO2 in medical air was administered through the tracheostomy tube. Subsequent behaviours were video-recorded and key physiological variables were evaluated using an anaesthetic monitor and the frequent sampling of arterial blood (albeit with inconsistent inter-sample intervals). After the study, behaviours were classified in an ethogram. At the onset of behaviours categorised as "vigorous movement extremities", "opisthotonos" and "agonal gasping" pH values (range) were: 6.74-7.34; 6.66-6.96 and 6.65-6.87, while PaCO2 (kPa) was 4.6-42.2, 24.4-51.4 and 29.1-47.6. Based upon these values, we conclude that the pigs were probably unconscious at the onset of "opisthotonos" and "agonal gasping", but some were probably conscious at the onset of "vigorous movements".
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Affiliation(s)
- Bente Wabakken Hognestad
- Department of Companion Animal Clinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 1433 Ås, Norway
| | - Nora Digranes
- Department of Companion Animal Clinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 1433 Ås, Norway
| | - Vigdis Groven Opsund
- Department of Production Animal Clinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 1433 Ås, Norway
| | - Arild Espenes
- Department of Preclinical Sciences and Pathology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 1433 Ås, Norway
| | - Henning Andreas Haga
- Department of Companion Animal Clinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 1433 Ås, Norway
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Mirra A, Gamez Maidanskaia E, Carmo LP, Levionnois O, Spadavecchia C. How is depth of anaesthesia assessed in experimental pigs? A scoping review. PLoS One 2023; 18:e0283511. [PMID: 36952576 PMCID: PMC10035875 DOI: 10.1371/journal.pone.0283511] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 03/09/2023] [Indexed: 03/25/2023] Open
Abstract
BACKGROUND Despite the large number of pigs involved in translational studies, no gold standard depth of anaesthesia indicators are available. We undertook a scoping review to investigate and summarize the evidence that sustains or contradicts the use of depth of anaesthesia indicators in this species. METHODS Medline, Embase and CAB abstract were searched up to September 22nd 2022. No limits were set for time, language and study type. Only original articles of in vivo studies using pigs or minipigs undergoing general anaesthesia were included. The depth of anaesthesia indicators reported in the selected papers were divided in two categories: A, indicators purposely investigated as method to assess depth of anaesthesia; B, indicators reported but not investigated as method to assess depth of anaesthesia. RESULTS Out of 13792 papers found, 105 were included after the screening process. Category A: 17 depth of anaesthesia indicators were found in 19 papers. Studies were conducted using inhalant anaesthetics as the main anaesthetic agent in the majority of the cases (13/19 = 68.4%), while 3/19 (15.8%) used propofol. The most investigated depth of anaesthesia indicators were bispectral index (8/19 = 42.1%) and spectral edge frequency 95% (5/19 = 26.3%). Contrasting results about the specific usefulness of each depth of anaesthesia indicators were reported. Category B: 23 depth of anaesthesia indicators were found in 92 papers. The most reported depth of anaesthesia indicators were: motor response following a stimulus (37/92 = 40.2%), depth of anaesthesia scores (21/92 = 23.3%), bispectral index (16/92 = 17.8%) and spectral edge frequency 95% (9/92 = 9.8%). CONCLUSION Results highlight the lack of scientifically valid and reliable indicators to ensure adequate depth of anaesthesia in pigs.
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Affiliation(s)
- Alessandro Mirra
- Anaesthesiology and Pain Therapy Section, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Ekaterina Gamez Maidanskaia
- Anaesthesiology and Pain Therapy Section, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Luís Pedro Carmo
- Department of Clinical Research und Public Health (DCR-VPH), Vetsuisse Faculty, Veterinary Public Health Institute, University of Bern, Bern, Switzerland
- Norwegian Veterinary Institute, Ås, Norway
| | - Olivier Levionnois
- Anaesthesiology and Pain Therapy Section, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Claudia Spadavecchia
- Anaesthesiology and Pain Therapy Section, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Bern, Switzerland
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Mirra A, Spadavecchia C, Levionnois O. Correlation of Sedline-generated variables and clinical signs with anaesthetic depth in experimental pigs receiving propofol. PLoS One 2022; 17:e0275484. [PMID: 36174080 PMCID: PMC9522294 DOI: 10.1371/journal.pone.0275484] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 09/16/2022] [Indexed: 11/19/2022] Open
Abstract
Most of currently available electroencephalographic (EEG)-based tools to assess depth of anaesthesia have not been studied or have been judged unreliable in pigs. Our primary aim was to investigate the dose-effect relationship between increasing propofol dose and variables generated by the EEG-based depth of anaesthesia monitor Sedline in pigs. A secondary aim was to compare the anaesthetic doses with clinical outcomes commonly used to assess depth of anaesthesia in this species. Sixteen juvenile pigs were included. Propofol infusion was administered at 10 mg kg-1 h-1, increased by 10 mg kg-1 h-1 every 15 minutes, and stopped when an EEG Suppression ratio >80% was reached. Patient state index, suppression ratio, left and right spectral edge frequency 95%, and outcomes from commonly used clinical methods to assess depth of anaesthesia in pigs were recorded. The best pharmacodynamic model was assessed for Patient state index, suppression ratio, left and right spectral edge frequency 95% in response to propofol administration. The decrease of Patient state index best fitted to an inhibitory double-sigmoid model (including a plateau phase). The increase of suppression ratio fitted a typical sigmoid Emax model. No relevant relationship could be identified between spectral edge frequency 95% values and propofol administration. A large variability in clinical outcomes was observed among pigs, such that they did not provide a reliable evaluation of propofol dose. The relationship between propofol dose and Patient state index/suppression ratio described in the present study can be used for prediction in future investigations. The evaluation of depth of anaesthesia based on common clinical outcomes was not reliable.
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Affiliation(s)
- Alessandro Mirra
- Section of Anaesthesiology and Pain Therapy, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Claudia Spadavecchia
- Section of Anaesthesiology and Pain Therapy, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Olivier Levionnois
- Section of Anaesthesiology and Pain Therapy, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Bern, Switzerland
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Nociception-Induced Changes in Electroencephalographic Activity and FOS Protein Expression in Piglets Undergoing Castration under Isoflurane Anaesthesia. Animals (Basel) 2022; 12:ani12182309. [PMID: 36139169 PMCID: PMC9494976 DOI: 10.3390/ani12182309] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 08/31/2022] [Indexed: 11/16/2022] Open
Abstract
The objective of this study was to investigate the electroencephalographic reaction pattern and FOS protein expression in male piglets undergoing surgical castration under light isoflurane anaesthesia with or without local anaesthesia. The experiment was conducted under isoflurane anaesthesia to exclude the effect of the affective components of pain on the measurements. Changes in the oscillatory activity of the cerebral cortex over a 90 s period after noxious stimulation or simulated interventions were analysed. FOS expression was determined postmortem by performing immunohistochemistry in the dorsal horn of the spinal cord. The analysis of the response to an interdigital pinch revealed a biphasic reaction pattern in the electroencephalogram (EEG) that similarly was observed for the surgical stimuli during the castration procedure in the group without analgesia. This EEG response was attenuated or altered by the application of local anaesthetics. Immunohistochemical staining for FOS indicated a lower expression in the handling and in three local anaesthetic groups than in the animals castrated without pain relief. The findings indicate that EEG and FOS expression may serve as indicators for nociception in piglets under light isoflurane anaesthesia. A lower activation of nociceptive pathways occurs during castration after the application of local anaesthetics. However, EEG and FOS analyses should be combined with additional parameters to assess nociception, e.g., haemodynamic monitoring.
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Ryden A, Fisichella S, Perchiazzi G, Nyman G. Comparison of two injectable anaesthetic techniques on induction and subsequent anaesthesia in pigs. Lab Anim 2021; 55:540-550. [PMID: 34325556 DOI: 10.1177/00236772211029810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Pig experiments often require anaesthesia, and a rapid stress-free induction is desired. Induction drugs may alter the subsequent anaesthesia. Therefore, the aim of the present study was to compare, in pigs, the effects of two different injectable anaesthetic techniques on the induction and on the physiological variables in a subsequent eight hours of total intravenous anaesthesia (TIVA). Twelve domestic castrates (Swedish Landrace/Yorkshire) 27‒31 kg were used. The pigs were randomly assigned to different induction drug combinations of zolazepam-tiletamine and medetomidine intramuscularly (ZTMe) or midazolam, ketamine intramuscularly and fentanyl intravenously (MiKF). Time from injection to unconsciousness was recorded and the ease of endotracheal intubation assessed. The TIVA infusion rate was adjusted according to the response exhibited from the nociceptive stimulus delivered by mechanically clamping the dewclaw. The time from injection to unconsciousness was briefer and intubation was easier in the ZTMe group. Results from the recorded heart rate, cardiac index and arterial blood pressure variables were satisfactorily preserved and cardiovascular function was maintained in both groups. Shivering was not observed in the ZTMe group, but was observed in four of the pigs in the MiKF group. The requirement of TIVA was lower in the ZTMe group. In conclusion, ZTMe had better results than MiKF in areas such as shorter induction time, better intubation scoring results and less adjustment and amount of TIVA required up to six hours of anaesthesia. The results may have been due to a greater depth of anaesthesia achieved with the ZTMe combination at the dose used.
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Affiliation(s)
- Anneli Ryden
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Sweden
| | - Sheila Fisichella
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Sweden
| | - Gaetano Perchiazzi
- Hedenstierna Laboratory, Uppsala University, Sweden
- Department of Anaesthesia, Operation and Intensive Care, Uppsala University Hospital, Sweden
| | - Görel Nyman
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Sweden
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Haga HA, Lervik A, Nordgreen J. Inhibition and facilitation of nociceptively evoked muscular activity by fentanyl or dexmedetomidine in isoflurane-anaesthetized pigs. Vet Anaesth Analg 2021; 48:230-238. [PMID: 33526309 DOI: 10.1016/j.vaa.2020.09.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 05/15/2020] [Accepted: 09/02/2020] [Indexed: 12/26/2022]
Abstract
OBJECTIVE To investigate motor and cardiovascular responses to dexmedetomidine or fentanyl in isoflurane-anaesthetized pigs. STUDY DESIGN Experimental, balanced, block randomized, two-group design. ANIMALS A group of 16 crossbred pigs, 55 ± 8 days (mean ± standard deviation) old. METHODS Deltoid electromyography (EMG) was recorded during isoflurane anaesthesia. Electrical stimulation using 5, 10, 20 and 40 mA of the distal right thoracic limb elicited a nociceptive withdrawal reflex (NWR), quantified by the area under the curve (AUC) for the simulation intensity versus EMG amplitude response curve. Latency to movement evoked by clamping a claw for maximum 60 seconds was noted. Arterial blood pressure and pulse rate were recorded. Data were sampled at baseline and during dexmedetomidine 0.25, 0.5, 1.0, 2.0, 4.0 and 8.0 μg kg-1 hour-1 or fentanyl 5, 10, 20, 40, 80 and 160 μg kg-1 hour-1 infusions. The influence of infusion rate on NWR AUC and spontaneous EMG was analysed using a mixed model, with p < 5%. RESULTS NWR AUC increased at fentanyl 5 μg kg-1 hour-1 but decreased at fentanyl 40, 80 and 160 μg kg-1 hour-1 and dexmedetomidine 4.0 and 8.0 μg kg-1 hour-1. All pigs at fentanyl 80 μg kg-1 hour-1, and three pigs at dexmedetomidine 8.0 μg kg-1 hour-1 had mechanical latencies greater than 60 seconds. Spontaneous EMG activity increased accompanied by visually evident 'shivering' at fentanyl 5, 10 and 20 μg kg-1 hour-1 but decreased at dexmedetomidine 2, 4 and 8 μg kg-1 hour-1. Clinically relevant effects of increasing infusion rates on blood pressure or pulse rate were not observed. CONCLUSION AND CLINICAL RELEVANCE If anaesthetic plane or antinociception is evaluated in pigs, response to claw clamping and NWR will not necessarily give uniform results when comparing drugs. If only one method is used, results should be interpreted cautiously.
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Affiliation(s)
| | - Andreas Lervik
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Norway
| | - Janicke Nordgreen
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Norway
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Lervik A, Toverud SF, Krontveit R, Haga HA. A comparison of respiratory function in pigs anaesthetised by propofol or alfaxalone in combination with dexmedetomidine and ketamine. Acta Vet Scand 2020; 62:14. [PMID: 32164761 PMCID: PMC7066810 DOI: 10.1186/s13028-020-0512-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 02/29/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND General anaesthesia in pigs maintained with intravenous drugs such as propofol may cause respiratory depression. Alfaxalone gives less respiratory depression than propofol in some species. The aim of the investigation was to compare respiratory effects of propofol-ketamine-dexmedetomidine and alfaxalone-ketamine-dexmedetomidine in pigs. Sixteen pigs premedicated with ketamine 15 mg/kg and midazolam 1 mg/kg intramuscularly were anaesthetised with propofol or alfaxalone to allow endotracheal intubation, followed by propofol 8 mg/kg/h or alfaxalone 5 mg/kg/h in combination with ketamine 5 mg/kg/h and dexmedetomidine 4 µg/kg/h given as a continuous infusion for 60 min. The pigs breathed spontaneously with an FIO2 of 0.21. Oxygen saturation (SpO2), end-tidal CO2 concentration (PE'CO2), respiratory rate (fR) and inspired tidal volume (VT) were measured, and statistically compared between treatments. If the SpO2 dropped below 80% or if PE'CO2 increased above 10.0 kPa, the pigs were recorded as failing to complete the study, and time to failure was statistically compared between treatments. RESULTS Alfaxalone treated pigs had significantly higher respiratory rates and lower PE'CO2 than propofol treated pigs, with a fR being 7.3 /min higher (P = 0.01) and PE'CO2 0.8 kPa lower (P = 0.05). SpO2 decreased by 0.6% and fR by 1.0 /min per kg increase in body weight in both treatment groups. Three of eight propofol treated and two of eight alfaxalone treated pigs failed to complete the study, and times to failure were not significantly different between treatments (P = 0.75). CONCLUSIONS No major differences in respiratory variables were found when comparing treatments. Respiratory supportive measures must be available when using both protocols.
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Lervik A, Raszplewicz J, Ranheim B, Solbak S, Toverud SF, Haga HA. Dexmedetomidine or fentanyl? Cardiovascular stability and analgesia during propofol-ketamine total intravenous anaesthesia in experimental pigs. Vet Anaesth Analg 2018; 45:295-308. [DOI: 10.1016/j.vaa.2017.08.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 07/13/2017] [Accepted: 08/29/2017] [Indexed: 10/18/2022]
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Blood biochemical changes in pigs after infusion with acetate-buffered or lactate-buffered crystalloid solutions. Lab Anim (NY) 2016; 44:268-73. [PMID: 26091132 DOI: 10.1038/laban.739] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 12/18/2014] [Indexed: 01/15/2023]
Abstract
Perioperative fluid therapy is an important component of many medical procedures with animals. Buffered crystalloid solutions avoid inducing metabolic acidosis, but lactated solutions can elevate blood lactate concentrations and acetated solutions have not been thoroughly investigated using large animals. Here, the authors compare blood biochemical parameters in 20 juvenile pigs after perioperative fluid administration of an acetate-buffered solution (Elo-Mel isoton, EMI) or a lactate-buffered solution (lactated Ringer's solution, LRS). The authors measured blood lactate, glucose and electrolyte concentrations before and after administering the test fluid during surgery. Blood lactate concentration after administration was significantly higher in pigs that received LRS than in pigs that received EMI, but glucose and electrolyte concentrations did not differ significantly between treatment groups before or after administration. These findings suggest that EMI might be a preferable option for perioperative fluid therapy in pigs.
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Spadavecchia C, Haga H, Ranheim B. Concentration-dependent isoflurane effects on withdrawal reflexes in pigs and the role of the stimulation paradigm. Vet J 2012; 194:375-9. [DOI: 10.1016/j.tvjl.2012.04.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 04/17/2012] [Accepted: 04/18/2012] [Indexed: 10/28/2022]
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Benson E, Alphin R, Rankin M, Caputo M, Kinney C, Johnson A. Evaluation of EEG based determination of unconsciousness vs. loss of posture in broilers. Res Vet Sci 2012; 93:960-4. [DOI: 10.1016/j.rvsc.2011.12.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Revised: 11/18/2011] [Accepted: 12/05/2011] [Indexed: 11/29/2022]
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